This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kvitko, B. H.
Right arrow Articles by Collmer, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kvitko, B. H.
Right arrow Articles by Collmer, A.

 Previous Article  |  Next Article 

Journal of Bacteriology, November 2007, p. 8059-8072, Vol. 189, No. 22
0021-9193/07/$08.00+0     doi:10.1128/JB.01146-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Identification of Harpins in Pseudomonas syringae pv. tomato DC3000, Which Are Functionally Similar to HrpK1 in Promoting Translocation of Type III Secretion System Effectors{triangledown} ,{dagger}

Brian H. Kvitko,{ddagger} Adela R. Ramos,{ddagger} Joanne E. Morello, Hye-Sook Oh, and Alan Collmer*

Department of Plant Pathology, Cornell University, Ithaca, New York 14853

Received 20 July 2007/ Accepted 6 September 2007

Harpins are a subset of type III secretion system (T3SS) substrates found in all phytopathogenic bacteria that utilize a T3SS. Pseudomonas syringae pv. tomato DC3000 was previously reported to produce two harpins, HrpZ1 and HrpW1. DC3000 was shown here to deploy two additional proteins, HopAK1 and HopP1, which have the harpin-like properties of lacking cysteine, eliciting the hypersensitive response (HR) when partially purified and infiltrated into tobacco leaves, and possessing a two-domain structure similar to that of the HrpW1 class of harpins. Unlike the single-domain harpin HrpZ1, the two-domain harpins have C-terminal enzyme-like domains: pectate lyase for HopAK1 and lytic transglycosylase for HopP1. Genetic techniques to recycle antibiotic markers were applied to DC3000 to generate a quadruple harpin gene polymutant. The polymutant was moderately reduced in the elicitation of the HR and translocation of the T3SS effector AvrPto1 fused to a Cya translocation reporter, but the mutant was unaffected in the secretion of AvrPto1-Cya. The DC3000 hrpK1 gene encodes a putative translocator in the HrpF/NopX family and was deleted in combination with the four harpin genes. The hrpK1 quadruple harpin gene polymutant was strongly reduced in HR elicitation, virulence, and translocation of AvrPto1-Cya into plant cells but not in the secretion of representative T3SS substrates in culture. HrpK1, HrpZ1, HrpW1, and HopAK1, but not HopP1, were independently capable of restoring some HR elicitation to the hrpK1 quadruple harpin gene polymutant, which suggests that a consortium of semiredundant translocators from three protein classes cooperate to form the P. syringae T3SS translocon.

* Corresponding author. Mailing address: Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phone: (607) 255-7843. Fax: (607) 255-8835. E-mail: arc2{at}cornell.edu

{triangledown} Published ahead of print on 14 September 2007.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

{ddagger} B.H.K. and A.R.R. contributed equally to this work.

Journal of Bacteriology, November 2007, p. 8059-8072, Vol. 189, No. 22
0021-9193/07/$08.00+0     doi:10.1128/JB.01146-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Morello, J. E., Collmer, A. (2009). Pseudomonas syringae HrpP Is a Type III Secretion Substrate Specificity Switch Domain Protein That Is Translocated into Plant Cells but Functions Atypically for a Substrate-Switching Protein. J. Bacteriol. 191: 3120-3131 [Abstract] [Full Text]  
  • Mohr, T. J., Liu, H., Yan, S., Morris, C. E., Castillo, J. A., Jelenska, J., Vinatzer, B. A. (2008). Naturally Occurring Nonpathogenic Isolates of the Plant Pathogen Pseudomonas syringae Lack a Type III Secretion System and Effector Gene Orthologues. J. Bacteriol. 190: 2858-2870 [Abstract] [Full Text]  
  • Oh, H.-S., Kvitko, B. H., Morello, J. E., Collmer, A. (2007). Pseudomonas syringae Lytic Transglycosylases Coregulated with the Type III Secretion System Contribute to the Translocation of Effector Proteins into Plant Cells. J. Bacteriol. 189: 8277-8289 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»